According to this invention, the encoded data amount of an image and its area attribute information can be encoded to a target amount or less by one input operation of image data, and an input image can be efficiently encoded in accordance with the property of the image. For this purpose, an encoding sequence unit sets an initial quantization matrix table for an image encoding unit in accordance with a mode set by a mode setting unit, and sets parameters associated with attribute rewrite for an attribute rewrite unit. When an image is input, encoded image data generated by the image encoding unit is stored in a memory. Attribute-encoded data generated by an attribute encoding unit is also stored in the memory. The first counter counts an encoded-image data amount, and the second counter counts an attribute-encoded data amount. When the sum of these encoded data exceeds a target amount, the encoding sequence control unit updates the quantization matrix table for the image encoding unit, and causes the image encoding unit to continue encoding. The updated quantization matrix table is set for a re-encoding unit, and encoded data stored in the memory is re-encoded.
Legal claims defining the scope of protection, as filed with the USPTO.
1. An image encoding apparatus which receives image data, and encodes and outputs the image data and area information, comprising: input mode setting means for setting whether input image data is a character line image or a halftone image; image encoding means for encoding image data in accordance with a first parameter for determining a compression ratio; re encoding means for decoding encoded data generated by said image encoding means, and re encoding the decoded data in accordance with a second parameter for determining a compression ratio; attribute detection means for detecting area attribute information of input image data; attribute correction means for correcting the area attribute information in accordance with a third parameter; attribute encoding means for encoding the area attribute information corrected by said attribute correction means; initial parameter setting means for determining the first parameter and the third parameter in accordance with an input mode set by said input mode setting means, and respectively setting the first parameter and the third parameter for said image encoding means and said correction means; monitoring means for monitoring a total code amount as a sum of an image encoded data amount generated by said image encoding means and an attribute encoded data amount generated by said attribute encoding means in accordance with the set parameters during input of a 1 page image, and determining whether the total code amount is not less than a predetermined value; parameter update means for, when said monitoring means determines that the total code amount is not less than the predetermined value, (a) updating the first parameter set for said image encoding means to a new first parameter of a higher compression ratio, and causing said image encoding means to continue encoding of image data, and (b) setting a second parameter equal to the updated new first parameter for said re encoding means, and causing said re encoding means to re encode image encoded data before the total code amount is not less than the predetermined value; and control means for, when said parameter update means updates the parameters, (a) causing said re encoding means to re encode, in accordance with the second parameter, encoded data generated by said image encoding means before the new first parameter is set, and storing the re encoded data as encoded data generated by said image encoding means after the new first parameter is set, and (b) storing the encoded data generated by said image encoding means after the new first parameter is set as succeeding encoded data.
2. The apparatus according to claim 1 , wherein when said input mode setting means represents that a character line image is set, said initial parameter setting means sets, as the third parameter, information which instructs said correction means to forcibly rewrite information representing a character line image/halftone in the area information detected by said attribute detection means into information representing a character line image, and when said input mode setting means represents that a halftone image is set, said initial parameter setting means sets, as the third parameter, information which instructs said correction means to forcibly rewrite information representing a character line image/halftone in the area information detected by said attribute detection means into information representing a halftone.
3. The apparatus according to claim 1 , wherein the mode set by said input mode setting means includes an auto mode, and when the auto mode is set, said initial parameter setting means sets, as the third parameter, information which instructs said correction means to pass the area information detected by said attribute detection means without correcting the area information.
4. An image encoding method of receiving image data, and encoding and outputting the image data and area information, comprising: an input mode setting step of setting whether input image data is a character line image or a halftone image; an image encoding step of encoding image data in accordance with a first parameter for determining a compression ratio; a re encoding step of decoding encoded data generated in the image encoding step, and re encoding the decoded data in accordance with a second parameter for determining a compression ratio; an attribute detection step of detecting area attribute information of input image data; an attribute correction step of correcting the area attribute information in accordance with a third parameter; an attribute encoding step of encoding the area attribute information corrected in the attribute correction step; an initial parameter setting step of determining the first parameter and the third parameter in accordance with an input mode set in the input mode setting step, and respectively setting the first parameter and the third parameter for the image encoding step and the correction step; a monitoring step of monitoring a total code amount as a sum of an image encoded data amount generated in the image encoding step and an attribute encoded data amount generated in the attribute encoding step in accordance with the set parameters during input of a 1 page image, and determining whether the total code amount is not less than a predetermined value; a parameter update step of, when the total code amount is determined in the monitoring step to be not less than the predetermined value, (a) updating the first parameter set for the image encoding step to a new first parameter of a higher compression ratio, and continuing encoding of image data, and (b) setting a second parameter equal to the updated new first parameter for the re encoding step, and re encoding image encoded data before the total code amount is not less than the predetermined value; and a control step of, when the parameters are updated in the parameter update step, (a) re encoding, in the re encoding step in accordance with the second parameter, encoded data generated in the image encoding step before the new first parameter is set, and storing the re encoded data as encoded data generated in the image encoding step after the new first parameter is set, and (b) storing the encoded data generated in the image encoding step after the new first parameter is set as succeeding encoded data.
5. A computer readable storage medium having stored thereon a computer program which when executed by a computer causes the computer to function as: input mode setting means for setting whether input image data is a character line image or a halftone image; image encoding means for encoding image data in accordance with a first parameter for determining a compression ratio; re encoding means for decoding encoded data generated by said image encoding means, and re encoding the decoded data in accordance with a second parameter for determining a compression ratio; attribute detection means for detecting area attribute information of input image data; attribute correction means for correcting the area attribute information in accordance with a third parameter; attribute encoding means for encoding the area attribute information corrected by said attribute correction means; initial parameter setting means for determining the first parameter and the third parameter in accordance with an input mode set by said input mode setting means, and respectively setting the first parameter and the third parameter for said image encoding means and said correction means; monitoring means for monitoring a total code amount as a sum of an image encoded data amount generated by said image encoding means and an attribute encoded data amount generated by said attribute encoding means in accordance with the set parameters during input of a 1 page image, and determining whether the total code amount is not less than a predetermined value; parameter update means for, when said monitoring means determines that the total code amount is not less than the predetermined value, (a) updating the first parameter set for said image encoding means to a new first parameter of a higher compression ratio, and causing said image encoding means to continue encoding of image data, and (b) setting a second parameter equal to the updated new first parameter for said re encoding means, and causing said re encoding means to re encode image encoded data before the total code amount is not less than the predetermined value; and control means for, when said parameter update means updates the parameters, (a) causing said re encoding means to re encode, in accordance with the second parameter, encoded data generated by said image encoding means before the new first parameter is set, and storing the re encoded data as encoded data generated by said image encoding means after the new first parameter is set, and (b) storing the encoded data generated by said image encoding means after the new first parameter is set as succeeding encoded data.
6. An image encoding apparatus which receives image data, and encodes and outputs the image data and area information, comprising: input mode setting means for setting whether input image data is a character line image or a halftone image; first image encoding means for encoding input image data in accordance with a first parameter for determining a compression ratio; second image encoding means for encoding the input image data in parallel with said first image encoding means in accordance with a second parameter higher in compression ratio than the first parameter; re encoding means for decoding image encoded data generated by said second image encoding means, and re encoding the decoded data in accordance with a third parameter for determining a compression ratio; attribute detection means for detecting area attribute information of input image data; attribute correction means for correcting the area attribute information in accordance with a fourth parameter; attribute encoding means for encoding the area attribute information corrected by said attribute correction means; initial parameter setting means for determining the first parameter, the second parameter, and the fourth parameter in accordance with an input mode set by said input mode setting means, and respectively setting the first parameter, the second parameter, and the fourth parameter for said first image encoding means, said second image encoding means, and said correction means; monitoring means for monitoring a total code amount as a sum of an image encoded data amount generated by said first image encoding means and an attribute encoded data amount generated by said attribute encoding means in accordance with the set parameters during input of a 1 page image, and determining whether the total code amount is not less than a predetermined value; parameter update means for, when said monitoring means determines that the total code amount is not less than the predetermined value, (a) updating the first parameter set for said first image encoding means to a new first parameter equal to the second parameter, updating the second parameter set for said second image encoding means to a new second parameter of a higher compression ratio, and causing said first image encoding means and said second image encoding means to continue encoding, and (b) setting the updated new second parameter as the third parameter for said re encoding means; and control means for, when said parameter update means updates the parameters, (a) storing encoded data generated by said second image encoding means before the new second parameter is set as encoded data by said first image encoding means before the new first parameter is set, (b) causing said re encoding means to re encode, in accordance with the third parameter, encoded data generated by said second image encoding means before the new second parameter is set, and storing the re encoded data as encoded data generated by said second image encoding means after the new second parameter is set, and (c) storing the encoded data generated by said first image encoding means after the new first parameter is set as succeeding encoded data.
7. The apparatus according to claim 6 , wherein when said input mode setting means represents that a character line image is set, said initial parameter setting means sets, as the fourth parameter, information which instructs said correction means to forcibly rewrite information representing a character line image/halftone in the area information detected by said attribute detection means into information representing a character line image, and when said input mode setting means represents that a halftone image is set, said initial parameter setting means sets, as the fourth parameter, information which instructs said correction means to forcibly rewrite information representing a character line image/halftone in the area information detected by said attribute detection means into information representing a halftone.
8. The apparatus according to claim 6 , wherein the mode set by said input mode setting means includes an auto mode, and when the auto mode is set, said initial parameter setting means sets, as the fourth parameter, information which instructs said correction means to pass the area information detected by said attribute detection means without correcting the area information.
9. An image encoding method of receiving image data, and encoding and outputting the image data and area information, comprising: an input mode setting step of setting whether input image data is a character line image or a halftone image; a first image encoding step of encoding input image data in accordance with a first parameter for determining a compression ratio; a second image encoding step of encoding the input image data in parallel with the first image encoding step in accordance with a second parameter higher in compression ratio than the first parameter; a re encoding step of decoding image encoded data generated in the second image encoding step, and re encoding the decoded data in accordance with a third parameter for determining a compression ratio; an attribute detection step of detecting area attribute information of input image data; an attribute correction step of correcting the area attribute information in accordance with a fourth parameter; an attribute encoding step of encoding the area attribute information corrected in the attribute correction step; an initial parameter setting step of determining the first parameter, the second parameter, and the fourth parameter in accordance with an input mode set in the input mode setting step, and respectively setting the first parameter, the second parameter, and the fourth parameter for the first image encoding step, the second image encoding step, and the correction step; a monitoring step of monitoring a total code amount as a sum of an image encoded data amount generated in the first image encoding step and an attribute encoded data amount generated in the attribute encoding step in accordance with the set parameters during input of a 1 page image, and determining whether the total code amount is not less than a predetermined value; a parameter update step of, when the total code amount is determined in the monitoring step to be not less than the predetermined value, (a) updating the first parameter set for the first image encoding step to a new first parameter equal to the second parameter, updating the second parameter set for the second image encoding step to a new second parameter of a higher compression ratio, and continuing encoding in the first image encoding step and the second image encoding step, and (b) setting the updated new second parameter as the third parameter for the re encoding step; and a control step of, when the parameters are updated in the parameter update step, (a) storing encoded data generated in the second image encoding step before the new second parameter is set as encoded data in the first image encoding step before the new first parameter is set, (b) re encoding, in the re encoding step in accordance with the third parameter, encoded data generated in the second image encoding step before the new second parameter is set, and storing the re encoded data as encoded data generated in the second image encoding step after the new second parameter is set, and (c) storing the encoded data generated in the first image encoding step after the new first parameter is set as succeeding encoded data.
10. A computer readable storage medium having stored thereon a computer program which when executed by a computer causes the computer to function as: input mode setting means for setting whether input image data is a character line image or a halftone image; first image encoding means for encoding input image data in accordance with a first parameter for determining a compression ratio; second image encoding means for encoding the input image data in parallel with said first image encoding means in accordance with a second parameter higher in compression ratio than the first parameter; re encoding means for decoding image encoded data generated by said second image encoding means, and re encoding the decoded data in accordance with a third parameter for determining a compression ratio; attribute detection means for detecting area attribute information of input image data; attribute correction means for correcting the area attribute information in accordance with a fourth parameter; attribute encoding means for encoding the area attribute information corrected by said attribute correction means; initial parameter setting means for determining the first parameter, the second parameter, and the fourth parameter in accordance with an input mode set by said input mode setting means, and respectively setting the first parameter, the second parameter, and the fourth parameter for said first image encoding means, said second image encoding means, and said correction means; monitoring means for monitoring a total code amount as a sum of an image encoded data amount generated by said first image encoding means and an attribute encoded data amount generated by said attribute encoding means in accordance with the set parameters during input of a 1 page image, and determining whether the total code amount is not less than a predetermined value; parameter update means for, when said monitoring means determines that the total code amount is not less than the predetermined value, (a) updating the first parameter set for said first image encoding means to a new first parameter equal to the second parameter, updating the second parameter set for said second image encoding means to a new second parameter of a higher compression ratio, and causing said first image encoding means and said second image encoding means to continue encoding, and (b) setting the updated new second parameter as the third parameter for said re encoding means; and control means for, when said parameter update means updates the parameters, (a) storing encoded data generated by said second image encoding means before the new second parameter is set as encoded data by said first image encoding means before the new first parameter is set, (b) causing said re encoding means to re encode, in accordance with the third parameter, encoded data generated by said second image encoding means before the new second parameter is set, and storing the re encoded data as encoded data generated by said second image encoding means after the new second parameter is set, and (c) storing the encoded data generated by said first image encoding means after the new first parameter is set as succeeding encoded data.
11. An image forming apparatus which receives a document image and forms a visible image on a predetermined printing medium, comprising: an image encoding apparatus defined in claim 1 which encodes an input document image and area information obtained from the document image; storage means for storing encoded data generated by said image encoding apparatus; decoding means for decoding the encoded data stored in said storage means; and image forming means for forming an image by correcting image data obtained by said decoding means on the basis of the area information.
12. An image forming apparatus which receives a document image and forms a visible image on a predetermined printing medium, comprising: an image encoding apparatus defined in claim 6 which encodes an input document image and area information obtained from the document image; storage means for storing encoded data generated by said image encoding apparatus; decoding means for decoding the encoded data stored in said storage means; and image forming means for forming an image by correcting image data obtained by said decoding means on the basis of the area information.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
August 1, 2005
December 16, 2008
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